JOIN US"Mullah Omar was killed on way from Quetta to North Waziristan," Xinhua quoted Afghanistan's TOLO television as saying. It did not provide details how he was killed and by whom.
An Afghan security official confirmed the killing, saying: "It is correct that Mullah Omar has been killed."
The US has announced a $10 million award for the rebel's capture or death.
The Afghan National Directorate for Security (NDS) said that Mullah Omar, who was Afghanistan's de facto head of state when the Taliban was in power from 1996 to 2001, had disappeared from Pakistan's Quetta city.
"We can confirm he (Mullah Omar) has disappeared from his hideout in Quetta for the past three or four days," Xinhua quoted Lutfullah Mashal of the spy agency as saying.
The Pakistani Taliban, which maintains close links with the Afghan Taliban, said the reports were not true.
"Tehreek-e-Taliban has strongly denied that Mulla Omar was killed ... as claimed by the Afghan intelligence agency," Geo TV said.
One report said that former Pakistani spy chief Hamid Gul, who is passionately anti-US, was with Mullah Omar when he came under attack. Gul told TimesNow television that this was was not true.
Mullah Omar's Taliban regime in Afghanistan had sheltered Al Qaeda chief Osama bin Laden in the years prior to the Sep 11 attack on the US.
That prompted the US to declare war on the Taliban and overthrow its regime with the help of the anti-Taliban Northern Alliance in Afghanistan.
Taliban fighters then fled to Pakistan in large numbers to regroup.
Mullah Omar is widely said to be living in hiding in Quetta, a Pakistani city close to the Afghan border. Pakistan, which played a key role in the Taliban's birth, says it has no idea of Mullah Omar's whereabouts.
The news of Mullah Omar's reported killing comes three weeks after US commandos shot dead Osama in Pakistan's Abbottabad city, triggering a row between Islamabad and Washington.